Two court cases have thrown a spotlight on the predicament of hundreds of thousands of former mineworkers in southern Africa who have received little or no compensation for occupational lung diseases that have left them debilitated and jobless.

Years of working in poorly ventilated mines, inhaling silica dust – present in high concentrations in deep-level goldmines – can lead to silicosis, a crippling and progressive disease caused by scarring of the lungs.

A study of former goldmine workers by the Aurum Institute, a non-profit health research organisation, found that nearly 25% had silicosis. The disease has no cure and sufferers are also more prone to tuberculosis, an infectious disease that is endemic in goldmining communities.

Across the region, 280,000 ex-mineworkers are estimated to be eligible for compensation under South Africa's Occupational Diseases in Mines and Works Act (Odimwa), but according to one study as few as 2% have received the applicable benefits they are entitled to.

Those who do manage to apply for compensation sometimes wait years to be paid, and the amounts they eventually receive are insignificant in the context of diseases that often leave them unable to work.

This could change after a constitutional court ruling earlier in March found that Thembekile Mankanyi, an ex-mineworker, could claim damages of more than of 2.6m rand ($366,440) from his former employer, AngloGold Ashanti, for a lung disease he acquired while working at one of their mines.

A high court judgment had previously found that he was ineligible for further compensation because he had already received a payment of R16,320 ($2,300) through Odimwa.

Mankanyi died from respiratory problems a week before the constitutional court ruling, but the judgment allows his family to return to court and pursue his claim. "Now, for the first time, the civil justice system can kick in," Mankayi's attorney, Richard Spoor, told IRIN.

Another case, which could also set a precedent, is expected to go to court in 2012 and involves 18 ex-mineworkers who developed silicosis and TB after working at the President Steyn goldmine in Welkom, a town in Free State Province. They are suing the mine's former parent company, Anglo American, for failing to adequately advise its subsidiaries on the safe operation of their mines.

The symptoms of silicosis can take over a decade to appear, by which time many miners have returned to their homes in rural areas of South Africa, Lesotho and Mozambique, where they are unlikely to be able access the two-yearly examinations that could make them eligible for compensation.

Thuthula Balfour-Kaipa, a health advisor to the Chamber of Mines of South Africa, pointed out that the overstretched public health system was struggling to deliver basic healthcare, "so when it comes to a miner who looks fairly well and needs a chest x-ray, they're not a priority".

Now, for the first time, the civil justice system can kick in. A joint project was launched in 2007 by the Chamber of Mines, the department of health, and the National Union of Mineworkers (NUM) to set up clinics with the sole purpose of providing medical examinations for mineworkers in areas where labour is sourced, but so far only two clinics have opened: one in KwaZulu-Natal province and one in Eastern Cape.

The project also allocated funding to the Medical Bureau for Occupational Diseases (MBOD), which falls under the department of health and administers Odimwa, to help address delays in compensation payouts but, according to Balfour-Kaipa, the money has not been used. "The [health] department has never quite agreed what the funding should be used for," she told IRIN.

The health department did not respond to questions from IRIN, but according to the NUM's health and safety chair, Peter Bailey, the backlog of claims at the MBOD was still "massive".

Spoor described South Africa's legislation regulating compensation for occupational injuries and diseases as "very outdated", and the system for implementing it as "decrepit". He also noted that mining company contributions to the compensation fund were trivial.

"If you look at the prevalence studies of these [occupational lung] diseases, then it's abundantly clear that this fund [should be] bankrupt, however, there's never any challenge on its funding because so few people claim what they're due." He added that there was little pressure to reform the compensation system because "injured workers are invariably unemployed workers, and they are poor and voiceless".

The Chamber of Mines has set up a mining industry occupational safety and health (Mosh) initiative, aimed at identifying industry best practices for managing silica dust, as well as other safety issues such as noise and underground falls, and encouraging mining companies to adopt them.

According to the Mosh team, the most effective ways of controlling dust are to install fine water-spray systems, and applying chemicals to underground walls that will cause the dust to stick to them. Installing large fans to ventilate shafts is also crucial.

No one knows exactly how effectively these techniques will reduce dust levels, and therefore the incidence of silicosis. Balfour-Kapia said dust was very difficult to measure. "Any way you measure [it], there's still a 25% margin of error." And because silicosis takes so many years to manifest, "we can only know in years to come whether these measures have worked".

She said the incidence of silicosis had levelled off at about 1,600 cases per year, compared to 3,000 a year in 1998.

Bailey, of the NUMm maintained said that mines have made progress in implementing safety measures, and that the presence of health and safety representatives had empowered workers to exercise their rights to a safe working environment.

Spoor, however, was unconvinced. He said the lack of sanctions against mines that failed to comply with safety guidelines, and the small amounts they were currently required to pay into the compensation fund, meant there was no incentive for employers to look after their workers.